'use strict';
var single_element = function(collection){
    let result=[];
    for(let i in collection){
        if(i%2!=0){
            result.push(collection[i]);
        }
    }
    for(let i=0;i<result.length;i++){
        let num=0;
        for(let j=i+1;j<result.length;j++){
            if(result[i]==result[j]){
                result.splice(j,1);
                j--;
                num++;
            }
        }
        if(num>0){
            result.splice(i,1);
            i--;
        }
    }
    console.log(result);
    return result;
}
module.exports = single_element;
single_element([11, 11, 22, 11, 33, 11]);
